I'll just reiterate that the prospect of the wrath of the CAA descending on a carrier should they find (or even suspect) that a scheduled flight with bookings was not operated for commercial reasons is way beyond what compensation might be payable (which in the event has an actual take up of about 25% of the affected pax). Beyond two weeks ahead can be seen as a schedule change, inside that is seen as a cancellation.
Technical faults are something else, and you may lose flights because of that, although in the event of an extended fault the CAA once again would expect an air carrier to have the resources to cover this, hence the use of subchartered aircraft to cover issues, which really does cost the original carrier a fortune, but is expected.